Noodler's Ink Ahab Piston Fountain Pen - Navajo From Noodler's Ink - the Ahab Flex Nib Piston Fill Fountain Pen. Even with the classic design and a steel flex nib, this pen is remarkably affordable. Even with the classic design and a steel flex nib, this pen is remarkably affordable. Made from a celluloid derivative that makes it technically biodegradable- these pens should never be cleaned with alcohols.